First, obtain Visial Boy Advance Link 1.8.0. This is the GBA emulator; search for it using Google.
Next, get a ROM for either Falzar or Gregar version. Once again, search for "Mega Man Battle Network 6 ROM" using Google.
Also, you'll need to download Hamachi squared (the latest version of Hamachi.) What this does, in a nutshell, is create a pseudo LAN connection that you use to connect with other players. Take the time to learn how to use Hamachi.
Finally, you need to get a game save with everything on it. I believe the link on this page called "Saves" is where you get that.
After you have everything, you'll need to get into one of the Hamachi servers where BN6 players hang out. The most active one currently is probably "bn6ok2". It's not my server, and I don't remember the password, so I'll have to ask someone. I'll try to post again with that information.
This is what you need to do in order to be prepared to play. I'll post again later to detail how you start a game with somebody.
There's a game where you have one life, no continues, phoenix downs, save points, or pauses and the difficulty setting is random. It's called...the real world.
I download the Save. I open up the ROM. I go to Game shark snapshot and whenever i try to open up the file it says " cannot import snapshot Megaman_FXXBR6P . Current game is Megaman_FXXBR6E. Btw I am using the 2nd save.